starting interpolate funcs

lib/interpolate.c

@@ -0,0 +1,44 @@
+
+#include  <stdio.h>
+#include  <stdlib.h>
+#include  <unistd.h>
+#include  <string.h>
+#include  <math.h>
+
+#include  "../floatimg.h"
+
+int		verbosity;
+
+/* ---------------------------------------------------------------- */
+int fimg_interpolate(FloatImg *s1, FloatImg *s2, FloatImg *d, float coef)
+{
+int		picsize, idx;
+
+if (FIMG_TYPE_RGB != s1->type) {
+        fprintf(stderr, "%s : bad src 1 type %d on %p\n", __func__, 
+                                s1->type, s1);
+        return -8;
+        }
+
+if (FIMG_TYPE_RGB != s2->type) {
+        fprintf(stderr, "%s : bad src 2 type %d on %p\n", __func__, 
+                                s2->type, s2);
+        return -8;
+        }
+if (FIMG_TYPE_RGB != d->type) {
+        fprintf(stderr, "%s : bad dst type %d on %p\n", __func__, 
+                                d->type, d);
+        return -9;
+        }
+
+picsize = d->width * d->height * 2;
+
+for (idx=0; idx<picsize; idx++) {
+
+	d->R[idx] = (coef * s1->R[idx]) + ((1.0-coef) * s2->R[idx]);
+
+	}
+
+return -1;
+}
+/* ---------------------------------------------------------------- */